Staybolt structure



L'MUNHALL.

STAYBOLT STRUCIURE.

APPHCATION FILED IAN. 29, 1919.

Patented Jan. 13,1920.

Fl 5.2. 15 a 15 i.

WITNESSES 1. www- INVENTOR JOHN MUNHALL, PITTSBURGH, PENNSYLVANIA.

STAYIBOLT STRUCTURE.

To all whom it may concern:

Be it known that I, JOHN MUNHALL, a

vquired for diiferent lengths and sizes of bolts and which facilitates and reduces the cost of repairs.

The invention comprises the construction and arrangement of parts hereinafter described and claimed.

In the accompanying drawing, Figure 1 is a plan view of a stay-bolt showing the improved form of sleeve construction and the associated parts in section; and Figs. 2, 3 and i are sectional views of modified forms.

In the drawings, 1 indicates one form of stay-bolt to which the invention is applicable, this being one well known form of stay-bolt now on the market. 2 indicates the outside boiler sheet, and 3 the inside boiler sheet. The inner end of the stay-bolt is shown as threaded at 4:, and entering a threaded hole in the inner boiler sheet and being up-set at its extreme end, as at 5, all as is now common with stay-bolts. The opposite end of the stay-bolt is provided with a rounded head 6 which is substantially spherical as shown and which in constructions heretofore used, is seated in a suitably shaped sleeve which is threaded into the outside sheet 2 of the boiler and to the larger end of which sleeve is threaded the usual cap .7 for concealing the head of the bolt.

The improvements have to do entirely with the form of the sleeve itself. Heretofore this sleeve has been in a single piece, externally threaded for attaching it in the boiler sheet, and internally formed to provide a seat engaged by the head 6 of the bolt and on which seat said bolt head can rock slightly, the opening in the sleeve flaring toward its inner end to allow for move- 5 ment of the bolt.

With my improved construction, the

Specification of Letters Patent. Patented 'Jan. 13, 1920.

Application filed January 29, 1919. Serial No. 273,721.

sleeve is a composite one, comprising an outer and'inner member. The outer member or sleeve proper 8, is externally threaded as shown, substantially as in sleeves heretofore used, the inner end being slightly tapered to enable the sleeve to be tightly screwed into the boiler sheet, and the outer end of said threaded sleeve receiving the cap 7 as shown. Internally this sleeve is of smaller size toward its inner end than at its outer end, preferably by giving the same a uniform beveled or cone shape, as illustrated, or in any other convenient way forming such opening so that toward its inner end it has a portion smaller than at its outer end. Within this sleeve is abushing 9 also of tubular or sleeve shape, and which on its outer surface is made to conform to the shape of the opening through the sleeve 8, and preferably having an accurate and close fit therein. On account of this conformation of the interior of the sleeve and the exterior of the bushing, the latter can be readily entered into and removed from the sleeve from its outer end but cannot be forced through the sleeve, so that the two form in effect a composite sleeve comprising an outer sleeve proper and the internal lining or bushing thereof. This bushing at its outer end isshaped to provide a curved seat 10 for the bolt head 6, and has its narrowest portion at 11 immediately inwardly of the seat 10, so that the bolt head can rock slightly on said seat. Inwardly from the narrowest portion '1l,the opening through the bearing preferably .flares outwardly, as shown at 12, to allow .the shank of the bolt to assume difierent positions.

A number of different bushings will be provided for each diameter, and length of sleeve, the bushings differing either as to the shape of the seat 10 for the bolt head or the particular point at which the narrowest portion 11 is located, so as to accommodate bolts of different lengths and with different sizes of heads, and in this way a single sleeve, by merely providing several bushings of the necessary form, is adapted to receive bolts of different'lengths and different sizes and forms of heads. This reduces the number of sizes of sleeves which need be carried in stock.

Furthermore, when it becomes necessary exterior size, but it is merely necessary to remove the bushing and insert another one of the desired shape and size. In this way repairs are greatly cheapened and the waste of sleeves prevented.

When the interior of the sleeve and exterior of the bearing are formed onstraight tapering lines, as shown, a sufiiciently tight fit can be secured to prevent the escape of water or steam, or in any event, a perfect seal can be formed by means of the cap 7 by the use of a gasket between it and the sleeve it necessary, in some cases, however, and particularly where no end cap is used, it may be desirable to provide other sealing means, such for instance as shown in Fig. 2, in which the bushing at its outer end is provided with a flange 15 projecting outwardly over the end of the sleeve 8, and inserting between the end of said sleeve and said bearing a suitable gasket 16. The inward pressure of the bolt head obviously tends to draw the bushing tightly into the sleeve, thus compressing the gasket suiliciently to make a tight seal at this point.

In case the outer end of the bushing 9 is very thin, it may be strength ned to prevent deformation in shipping or handling by forming an annular rib 17 on its outer end, as shown in Fig. 3, which can be conveniently done by merely flanging the metal outwardly. In this case the outer end of the sleeve 8 may be provided with an annular recess 18, to receive said rib or flange 17, as also shown in Fig. 8.

The bushing 9 obviously can be used with any form or construction of sleeve. It is not necessary that the sleeve be separate from the boiler sheet. For instance, Fig. 4 shows the sleeve 8 integral with the boiler sheet 2, being formed either by fianging the boiler sheet around the opening outwardly, or by welding the sleeve to the opening in the boiler sheet, as indicated by the lines 19. Either method provides a sleeve integral with the boiler sheet, instead of one threaded thereonto as shown in the other views.

' The outer end ofthis integral sleeve will be externally threaded to receive the cap 7, and

internally said sleeveis tapered to receive the bushing 9.

Various other modifications obviously can be made in the form of the sleeve and of the bushing;

nation with a bolt having a rounded head, a

sleeve internally smooth and of smaller size toward its inner end than toward its outer end, and a bushing externally smooth and in shape conforming to the internal shape of the sleeve and provided at its outer end with seat for the bolt head.

2. In a stay-bolt construction, the combination of a bolt provided with a rounded head, a sleeve externally threaded to receive a closure and internally smooth and tapering from its outer end toward its inner end,

a bushing fitting in said sleeve and externally smooth and tapering from its outer end to its inner end and provided internally at its outer end with a seat for the bolt head.

3. A composite stay bolt sleeve comprising an outer part or sleeve externally threaded and internally smooth and of smaller cliaineter toward its inner end than at its outer end, and an internal bushing externally smooth and shaped toconform to the internal shape of the sleeve and internally being provided with a curved bolt head seat.

t. A composite stay-bolt sleeve comprising an outer part .or sleeve proper externally threaded and internally smooth and tapered from its outer to its inner end, and an inner part or bushing externally smooth and tapered from its outer to its inner end and being provided internally at its outer end with a curved bolt head seat.

In testimony whereof, I have hereunto set my hand. 7

JOHN MU N HALL. Witness:

ALICE A. TRILL. 

